Heat a large skillet to medium heat. Add the olive oil and chopped onions and cook for 4 minutes until slightly translucent.
Add the chopped garlic and cook for 1 minute until fragrant.
Pour in the crushed tomatoes and cook for 5 minutes. Then add the basil and oregano. Stir to combine and cook for an additional 5 minutes.
Add the erythritol and salt and pepper to taste and let simmer for 5 additional minutes.
In a large skillet, cook and break up the beef and sausage over medium heat until browned (about 10 minutes). Remove with a slotted spoon and set aside. Drain all but 2 tablespoons of the fat drippings from the skillet.
Add the onion and bell pepper and cook for 4 minutes until translucent. Add the garlic and cook for 1 minute until fragrant.
Return the beef and sausage mixture to the skillet and add 1/2 cup of marinara, oregano, salt, pepper, and basil. Cook together for 5 minutes. Remove from the heat.
Stir in 1/2 cup of mozzarella, the ricotta, parmesan, and egg yolks. Mix well.
Spread 1/2 cup of marinara in the bottom of an 8 x 8 inch baking dish. Place filling in the center of each shell and roll tightly. Place the manicotti in the baking dish. Pour marinara over the top. Cover and bake for 15 minutes in a 375 degree oven.
Remove the cover and sprinkle with remaining mozzarella. Bake uncovered for an additional 10 minutes or until bubbly.
Serve with a garnish of chopped basil and sprinkled parmesan.
The marinara sauce is a simple recipe and tastes great. If you prefer you can use Rao jarred marinara sauce. It is low carb and delicious. One final tip - you can use a toothpick to secure the top of each shell after filling. Make sure you remove them after baking.